Conventionally, a non-aqueous electrolyte battery as represented by a lithium ion battery have been receiving a demand for reduction in charging time. In order to meet such demand, the battery must be capable of being charged at high speed with a large current density. In addition, a non-aqueous electrolyte battery for automobiles have been receiving a demand for the ability to discharge high power at a large current density, in order to provide the automobile with sufficient accelerating property. When conducting charge and discharge at a large current density, internal resistance of the battery is important to improve the characteristics of maintaining battery capacity (high rate characteristics). The same can be said for other non-aqueous electrolyte batteries such as an electrical double layer capacitor and a lithium ion capacitor, and an electrical storage device.
In general, the cause of the internal resistance are electrical resistance of the constituting material, interface resistance between the constituting components, conductivity resistance of the ions which are the charged particles in the electrolyte solution, electrode reaction resistance, and the like. Therefore, each of the resistance need be decreased in order to decrease the internal resistance. Among them, one of the most important internal resistance is the interface resistance between the conductive substrate comprising a metal foil (for example, aluminum foil, copper foil and the like) and an active material layer. It has been known that one measure to decrease the interface resistance is to improve the adhesion in the interface.
In order to improve the adhesion between the current collector and the active material layer, a technique in which the current collector is coated with a conductive resin, and then a paste for forming an active material layer is coated thereon, has been conventionally proposed. Patent Literature 1 discloses a technique to form a conductive coating by coating a positive electrode current collector with a conductive coating including a conductive filler, vinyl butyral as a binding agent, and dibutyl phthalate as a plastcizing agent. Patent Literature 2 discloses a technique to form a conductive coating including a polyacrylic acid or a copolymer of an acrylic acid and an acrylic acid ester as a main binding agent, and a carbon powder as a conductive filler.